The invention relates to an intermeshed communication network, in which the setting up of connections between exchanges is initiated by forward messages.
Laid-open West German patent application No. DE-OS 35 11 431 and corresponding U.S. Pat. No. 4,741,027 disclose a channel selection method for an intermeshed communication network, in which exchanges are interconnected by communication lines. The setting up of connections between a calling subscriber, connected to an exchange, and a called subscriber, assigned to another exchange, is initiated by means of connection set-up messages. These messages are transmitted from the calling subscriber's exchange to all exchanges connected thereto and stored in these exchanges. In the called subscriber's exchange only the connection set-up message arriving first is used for establishing a connection to the calling subscriber station. In this way it is ensured that with an arbitrary network configuration of the intermeshed communication network the called subscriber is always found, as long as there is at least one communication path between the calling and the called subscriber. The connection set-up messages spread out in every direction from the calling subscriber to the called subscriber. On the basis of the direction in which they are spread out from the calling to the called subscriber they are designated as forward messages. On the communication path found thus a speech channel is seized sectionally from one exchange to the next and the connection is set up by means of a report-back message, which is transmitted through the found path in the opposite direction, from the called subscriber's exchange to the calling subscriber's exchange.
As a consequence of the movements of exchanges or failures of communication lines the network topology of an intermeshed communication network may change. Information about the network topology and the loads of the communication lines as well as further information of such an intermeshed communication network are summarized hereinafter under the term of network information. On the basis of this network information a network coordinator makes decisions about extensions and modifications as well as the type of exchanges and communication lines to be employed and reacts in this manner to the requirements of the communication network. The monitoring of the network is rendered difficult in that the network coordinator often changes its whereabouts for achieving these objects.